Tap fixture



p fi, 1946. c. E. MILLER 2,398,661

TAP FIXTURE Filed Sept. 8, 1944 2 Sheets-Sheet l l lzifardzm'lkr Aprii as, 1946.

c. E. MILLER 2,398,661

TAP FIXTURE Filed Sept 8, 194 2 Sheets-Sheet 2 Inventor z brdzm w by the required back-E Patented Apr. 16; 1946 St. Louis, Mo.

Application September 53, 1944, Seriai No. 553,296 s (on 51-4225) The present invention relates to new and useful improvements in tap fixtures or appliances, and has for its primary object to provide, in a manner as hereinafter set forth, a device of this character comprising a unique construction and arrangement whereby the accurate sharpening and backing ofi of the thread lead or tools of this character will be greatly expedited and simplified.

Another very important object is to provide a tap thread lead sharpening and backing-off fixture or the aforementioned character which is adapted to be readily adjusted to accommodate difierent sizes of tap flutes.

' Still another very important object of the invention is to provide a fixture of the character described comprising novel adjusting means whereon the tap thread lead may be readily had.

Other objects of the invention are to provide a tap lead sharpening and backing-off fixture which will be comparatively simple in construction, strong, durable, highly eficient and reliable in use, compact an which may b manufactured at low cost.

All of the foregoing and still further objects and advantages of the invention will become apparent from a study of the following specification, taken in connection with the accompanying drawings wherein like characters oi reference designate corresponding parts throughout the several views, and wherein:

Figure l is a view showing a fixture constructed in accordance with the present invention in use on one end of a tap.

Figure 2 is a view in longitudinal section through the device.

lgllre 3 is an elevational view, looking at the outer end or the device.

gure is a perspective view of the nature, showing the parts separated Figure 5 is an elevational view, looming at the inner end of the fixture.

Reten'ing now to the drawings in detail, it will be seen that reference character 5 designates generally a conventional tap, the thread lead 2 of which is to be sharpened and hacked ofl. Toward this end, the tap i is mounted for oscillation between the usual rinder and the thread rinding wheel 5.

The fixture constituting the present invention comprises a cylindrical metallic body 8 of suitable dimensions which is mounted on one end oi the tap I and which receives the center 4. Toward this end, the body 8 include an externally relead 2 engaged with a of the invention Y duced forward end portion l having a circumierential groove or channel 8 therein. A ring 9 is mounted for rotary adjustment on the end portion 3 oithe body mounted in the ring 9 and engaged in the groove or channel 3 for securing said ring in adjusted position. Projecting forwardly from the ring 9 is a lllg H. An arcuate plate ii is mounted for circumferential adjustment on the ring 9. Toward this end, the plate it has formed therein a slot 93 which accommodates a securing screw M. Formed integrally with one end portion of the plate 52 is a lug it. The lugs it and it are engageable in a pair or the flutes it of the tap l for securing the body it in the correct position thereon. This is shown to advantage in Figure 1 of the drawings.

The body 6 has formed in its forward end portion a concentric socket ll. A center point it is slidaoly mounted in the socket H. A coil spring as yieldingly urges the center point it outwardly in the socket ii. The center point it comprises a fiat upper portion it 'providing a shoulder 2!. The portion 2d of the center point is accommodates a pin 22 which is mounted in an opening 23 provided thereicr in the forward end portion l oi the body 5. The shoulder 29 is engageable with the pin 22 for limiting outward movement of the center point 38 under the influence of the coil spring is. The center point it is engageable in the usual center hole of the tap l. J

Mounted ior rotary adjustment in the rear end a portion of the body 3 is an eccentric center 2%. The center it! includes a metallic disc 25 having 3 therein an ofi-center hole or socket 26 for the centers a and t or a so mounted on one end of the tap i in in the tap.

reception or the grinder center i. The disc 25 is mounted for rota y adjustment in an off-center socket 2? which is provided therefor in the rear end portion of the body Screws 28 are threadedly mounted in the rear end portion or the body t and the heads thereof are encased with the disc 25 for securing said disc in adjusted position A groove or hen? in the disc 25 accommodates a screw driver or other justing said disc at loosened.

It is thought that the manner in which the device is used will be readily apparent from a consideration of the foregoing. Briefly, the body 6 is abutting engagement therewith. The center pin I8 is 611-- gazed in the usual center in the top I by the coil spring 59. Being spring-pressed, the point I8 automatically adjusts itself to any size or center The device is secured in the correct 1- the screws 2s have been 6. A set screw 3 8 is threadedly suitable tool for rotatably position on adjustable ring 8 with the lug l-l thereon and the coacting lug I! on the adjustable plate 12. The disc 25 is rotatably adjusted as may be necessary to get the correct center for the required backing oi! after the grinder center 4 has been engaged therein at 26.. The thread ;lead 2 is then engaged with the grinding wheel 5 and the tap i is oscillated in any suitable manner to accomplish the harpening and backing of! of said thread lead. I

It is believed that the many advantages or a fixture constructed in accordance with the present invention will be readily understood, and although preferred embodiments of the device are as illustrated and described, it is to be understood that changes in the details of construction and may be resorted to which will fall within the scope of the invention as claimed. What is claimed is:

1. A tap thread lead sharpening and backingof! fixture of the character described comprising I body, a center point a substantially cylindrical yieldingly mounted in one end portion of said body and engageable in the center in one end of a tap, I one end of the tap for rotation therewith, and

a rotatably adjustable disc mounted on the other means for connecting said body to said' in the combination and arrangement of parts a disc mounted for rotary adjustment in the socket, said disc having an ofl-center socket therein for the reception of a supporting center, and screws threadedly mounted in the body and including heads engaged with the disc for securing said disc in adjusted position.

3. A tap thread lead sharpening and backingof! fixture of the character described comprising a substantially cylinckical body engageable with one end or a tap, a ring mounted for rotary ad.-

,ior securin connecting the body to the tap i through the medium of the justment on one end portion oi aid body, meam said ring in adjusted position, a lug projecting from the ring, a lug mounted for adjustment on the ring, said lugs being engageable in the flutes oi the tap and cooperable with each other for securing the body to the tap for rotation therewith, and a rotatably adjustable center on the other end portion of the body for receiving "a supporting center.

'4. A tap threadlead sharpening and backingoi! fixture of the character described comprising a substantially cylindrica1 body engageable with one end of a tan, said body havinga concentric socket in one end portion and an oil-center socket in its other end portion, aspring-pressed center point slidably mounted in the first-named socket and engageable in the center of the tap, means for with, a disc mounted for rotary adjustment in the second-named socket, said disc having an off-center socket therein for the reception of a fOr securing the supporting center, and means disc in adjusted position.

5. A tap thread lead sharpening and backingofi fixture or the character described comprising a substantially cylindrical body engageable with one end of a tap; said body including an externally. reduced end portion having a concentric socket therein, a ring mounted for rotary adjustment on the reduced end portion of the body. means for securing said ring in adjusted position, a lug projecting from the ring, a plate adjustably mounted on the ring. a lug on said plate. the first and second-named lugs being engageable in flutes of the tap and cooperable for securing the body to said tap for rotation therewith, a center point slidably mounted in the socket and ,engageable in the center of the tap, a spring mounted in the socket and engaged with the center point for yieldingly urging same outwardly, the body having an oiL-center socket in its other end portion. a disc mounted for rotary adjustment in the second-named socket, said disc having an oil-center socket therein for the reception 45 of a supporting center, and means for ecuring the disc in adjusted position.

the tap for rotation there-: 

